The invention concerns an apparatus for demonstration of a motion development in time [i.e. changes in motion with respect to time, and more precisely an apparatus for a visual demonstration of path sections covered by movement of an object in equal time intervals.
Apparatus for demonstrating the development of motion in time is known where at any moment of time, an experiment records the path covered by an object. For this purpose, a measuring appliance similar to a pulley is used, which a string is laid out by means of which a weight pulls the moving object.] The pulley rotation is then detected by means of a photocell (PASCO Scientific 1994, Physics Experiments and computer Interfaces, Roseville, Calif. 95678-9011, USA). Apparatus for demonstration purposes also known that detects the moment when two or more photogates or photocells are passed by a moving object [and Impromax Mesco u{haeck over (c)}ila, SI-2312 Orehova vas).] In each of these systems, either the path covered by the object is measured depending upon the time of motion or upon the time in which the object covers a predetermined path.
In order to vividly demonstrate motion development, it is desirable to permanently mark the points in which a moving object is found at preselected time moments. This was achieved in an apparatus for demonstration disclosed in the U.S. Pat. No. 4,761,658. To a moving object, a paper strip is fastened onto which in equal time intervals ink is forced out from an ink jet head controlled by an oscillator.
For demonstrations, the above-mentioned apparatus uses expendable material like paper strips and ink.
The technical problem to be solved by the present invention is to construct an apparatus for demonstrating motion development in time that, on a straight line parallel to the trajectory of a moving object, points will be marked which correspond (i.e. preferably mapped 1:1) to points in which the moving object was located when the motion started and after multiples of an arbitrarily chosen time interval thereafter.
The above technical problem is solved by the first embodiment of the instant apparatus for demonstrating motion development in time characterized in that, on two parallel straight lines, a first and a second array of uniformly, and in both arrays equally spaced, photosensitive elements and light sources, respectively, are placed. Rails are provided upon which an object moves, in which rails are placed parallel to the arrays. A light source emitting a collimated light beam is placed on the object, which in any moment of time, the motion of the object illuminates one or two adjacent photosensitive elements. Each photosensitive element in a pertinent line of elements is connected to a first input of a logic AND gate, at whose second input clock pulses are provided and whose output is connected through a logic flip-flop element to the second array light source of this line of elements. Preferably, the clock is actuated at the moment when the object starts moving.
A solution to the technical problem is also provided by the second embodiment for demonstrating motion development in time according to the invention having the same mutual arrangement of arrays of photosensitive elements and light sources as well as an object with a light source for emitting a collimated light beam but where the photosensitive elements in each line of elements is connected through a first logic flip-flop element to the light source of the second array in the line and the light source affixed to the object emits a collimated light beam triggered by clock pulses. In this embodiment, at the origin and at the end of the array of the photosensitive elements in any of these two positions, between the light source emitting the collimated light beam and the corresponding photosensitive element, preferably a semitransparent mirror is mounted which partially reflects the collimated light beam to the appropriate one of two photosensitive elements fastened on the moving object and connected to the inputs of a second flip-flop element, whose output is connected to the on/off input switch of the clock.
Both embodiments of the apparatus for demonstrating motion development in time according to the invention are further characterized by a push button provided for resetting the apparatus before performing a demonstration, the push buttom being connected to an input of the first logic flip-flop element, and where the time interval duration between two subsequent clock pulses is adjustable.
Preferably, a tape measure is placed along the array of light emitting sources, the beginning or origin of the tape measure being situated at the first light emitting source of the array. The light source emitting a collimated light beam is a laser, the photosensitive elements are photoresistors and the light sources in the second array are preferably light-emitting diodes.
The apparatus of the invention is remarkable in that it conveys a visual demonstration of path sections covered by the object in equal time intervals and thereby makes it possible to picture whether the motion over particular moments is steady or accelerated. For demonstrations, the apparatus of the invention does not use expendable material such as paper strips and ink.